Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.
Performance monitoring of optical channels is an important step in the assessment and management of a stable optical system. Performance monitoring is often performed at various locations throughout an optical system using performance monitors such as optical channel monitors (OCMs). Parameters that can affect the system performance include the signal power, signal wavelength, optical signal-to-noise ratio (OSNR), polarization-mode-dispersion (PMD) and polarization-dependent-loss (PDL). Various OCMs are configured to monitor one or more of these parameters.
Producing a high resolution OCM is typically always challenging. Etalon techniques often suffer due to the required filter shape and deconvolution issues whilst Gaussian band shapes (e.g. from a grating spectrometer within the OCM) require a large beam to access a very high number of grating lines and so are challenged in terms of size and cost. Some techniques rely on the parallel acquisition of different channels or require serial scanning of multiple ports with additional fiber coupled switch requirement.